<!DOCTYPE html>

<html>

<head lang="en">
  <meta charset="UTF-8">
  <title></title>
  <style>
    * {
      margin: 0;
      padding: 0;
    }

    table {
      border-collapse: collapse;
      border-spacing: 0;
      border: 1px solid #c0c0c0;
      width: 500px;
      margin: 100px auto;
      text-align: center;
    }

    th {
      background-color: #09c;
      font: bold 16px "微软雅黑";
      color: #fff;
      height: 24px;
    }

    td {
      border: 1px solid #d0d0d0;
      color: #404060;
      padding: 10px;
    }

    .allCheck {
      width: 80px;
    }
  </style>
</head>

<body>
  <table>
    <tr>
      <th class="allCheck">
        <input type="checkbox" name="" id="checkAll"> <span class="all">全选</span>
      </th>
      <th>商品</th>
      <th>商家</th>
      <th>价格</th>
    </tr>
    <tr>
      <td>
        <input type="checkbox" name="check" class="ck">
      </td>
      <td>小米手机</td>
      <td>小米</td>
      <td>￥1999</td>
    </tr>
    <tr>
      <td>
        <input type="checkbox" name="check" class="ck">
      </td>
      <td>小米净水器</td>
      <td>小米</td>
      <td>￥4999</td>
    </tr>
    <tr>
      <td>
        <input type="checkbox" name="check" class="ck">
      </td>
      <td>小米电视</td>
      <td>小米</td>
      <td>￥5999</td>
    </tr>
  </table>
  <script>
    let checkAll=document.querySelector('#checkAll')
    let all=document.querySelector('.all')
    let cks=document.querySelectorAll('.ck')
    checkAll.addEventListener("click",function(){
      console.log(checkAll.checked);
      for(let i=0;i<cks.length;i++){
        cks[i].checked=checkAll.checked
      }
      if(checkAll.checked==true){
        all.innerHTML="取消"

      }else{
        all.innerHTML="全选"
      }

    })
    //给每个按钮注册一个监听
   for(let i=0;i<cks.length;i++){
     cks[i].addEventListener("click",function(){
       //触发一个按钮的事件都要重新对每一个按钮进行判断，这是一个过程
       for(let j=0;j<cks.length;j++){
         if(cks[j].checked===false){
           checkAll.checked=false
           return
         }else{
          checkAll.checked=true
         }
         
       }
       
     })
   }
   let date=new Date()
   console.log(date);

  </script>
</body>

</html>